Installation of underground electric cables for power transmission



June 27, 1933. G, MEERBECK 1,915,743

INSTALLATION OF UNDERGROUND ELECTRIC CABLES FOR POWER TRANSMISSION Fi led Nov. 19, 1951 flvvam Tag Patented June 27, 1933 g UNITED STATESPATENT OFFICE GOTTFRIED IEEBBEGI, OI OOLOGNE-IULHEIH, GERMANY, ASBIGNOR'10 NAAHLOOZE VENNOOTSCHAP HANDELIAATSCHAPPIJ' OABLON (CABLONCORPORATION), 01 THE HAGUE, NETHERLANDS INSTALLATION OF UNDERGROUNDELECTRIC CABLES FOB POWER TRANSMISSION Application filed November 18,1931, Serial No. 576,190, and in Germany November 25, 19 30.

It has previously been proposed to install electric high tensioninsulated or bare cables y as in pressure-resisting, gastight, steelpipes containing a pressure medium. For the purpose of obtainingareliable and durable gastight connection, the individual pipes aregenerally joined together in the usual way by welding and the cable isthen pulled through. Difliculties are encountered when the lengths ofpipes through which the electric cables have already been pulled throughhave to be connected together, or when gastight connecting sleeves haveto be provided over completed cable joints, since when the steel tubesand the flanges of the connecting sleeve have to be Welded the cablewhich lies in the interior of the pipe at a very small distance from thewelding points would be destroyed by the high welding temperature.

The present invention has for its object to provide a jointingarrangement for the pressure pipes of cable installations in which thedifficulties above referred to will be avoided and which will also allowa completed steel pipe joint to be cut open, whenever any cable repairsare necessary, and to re-establish it by welding, without endangeringthe cable which lies in the interior of the pipes or connecting sleeves.

Figures 1 and 2 of the accompanying drawing illustrate in longitudinalsection joints for pressure pipe cable installations according to theinvention, similar parts being indicated by the same reference letters.

As the cable joint itself is in no way different from the joints knownin practice, it has been merely indicated at p in Figure 1 and left outaltogether in Figure 2.

In Figure 1 g and '1' are the two cable ends connected together by thecable joint 17. This joint must, like the cable itself, be provided witha sufiiciently impervious and flexible covering serving as a membranefor the pressure, e. g. a lead covering of suitable thickness, by meansof which the pressure of the medium in the interior of the' joint box istransmitted to the interior of the cable joint. a and b are the two endsof the pressure pipe which are intended to be connected together by anappropriate construction, which will be resistant to pressure. For thispurpose the pipe ends are provided with ferrulesd and e having innerflanges fixed to the pipe ends a and b and having elongated turnedannular flanges n and 0. It is important that the curved parts (1 andeshall be bent in the'direction shown in the drawing, that is to saythey should extend away from the joint and that, in addition thereto,the flanges n and 0 which are a continuation of the curved parts, shallbeof suflicient length.

The said curved ferrules d and e with the annular flanges n and 0 whichare turned back may be obtained by pressing and be welded on to the pipeends a and 6 before the pipes are delivered.

A piece of pipe 0 of sufi'icientdength is drawn as connecting sleeveover the flanges n and 0 and is joined to the flanges tightly andsecurely by annular welding at f and g. In order to strengthen thestructure, use may also be made of shrinking rings 2' and k, which aredrawn over the connecting sleeve 0 and flanges and 0 respectively. Theferrules may also be provided with narrow ribs h for strengtheningpurposes.

Before the assembling, the sleeve is pushed over one of the pipe ends.After the cable has been installed, the sleeve 0 is pushed into theright position, the welding is effected at f and g and, if desired, theshrinking rings 71 and k are drawn over, whereby the joint is completed.It is to be understood that pipe joints as hereinbefore described may beprovided for the purpose of cable repairs also in such places of thepipe line where there are no cable joints.

The form of construction of pipe joints hereinbefore described has manyadvantages; thus, for instance, if it is desired to efl'ect any repairof the cable, it is easy to open the sleeve by simply cutting away thewelding seams f and g. It is just as easy to re-weld the sleeve when therepair is terminated without using any new parts. There is no difficultyin mak ing the flanges n and o of the ferrules of such a length thatfour, five or more repairs can be effected without using any newparts'for the ipe joint. In such case, the new welds 0f the flanges withthe sleeve 0 come to lie nearer and nearer to the middle of the sleeve,the first one for instance at approximately the lace indicated by thereference letters Z and m respectively. The cable joint is madeaccessible by removing the welding seams f and g by cutting, whereuponthe sleeve 0 is pushed aside, as shown in dotted lines in Fig. 1; afterthe re air has been effected, the pipe 0 is again pus ed over theflanges n and o and is re-welded thereto.

The use of turned-back ferrules with annular flanges has the furtheradvantage'that the welds are distant from the pipe and the cabletherein; therefore the heating of the cable during weldin is furtherreduced. Moreover, by circulatmg cold air or water or by .insertin moistmaterial in the hollow space of eac ferrule, the transmission of heatfrom the welds to the interior of the pipe can easily be racticallycompletely avoided.

It is to understood that the shape of the turned-back ferrules ma bedifl'erent from that shown in Fig. 1. or instance, instead of thecurvature it maybe angular, such as shown in Fig. 2 as long as thedirection of the turned-back flanges from the jointing an electric cableand flanges, and a connecting sleeve fitting on said flanges and weldedthereto, at the end edges whereby said welded ed es of the sleeve andflanges may be re eate ly cut off and re-welded to permit 0 access tothe cable oints.

In testimony whereof I have signed my name to this specification.

GOTTFRIED MEERBECK.

